Bis(dialkylamino)sulfur difluorides

ABSTRACT

Bis(dialkylamino)sulfur difluorides are new fluorinating agents.

O United States Patent [191 [111 3,888,924

Middleton June 10, 1975 BIS(DIALKYLAMINO)SULFUR [56] References Cited DIFLUORIDES OTHER PUBLICATIONS [75] Inventor: William Joseph Middleton, Chad Noth et al., Berichte (97) 1, pp. 202-206 (1964).

Ford, Pa. Lustig et al., Inorganic Chem. Vol. 4, No. 10 (1965) I P pp. 1444-1446. [73] Assgnee fi gz w gigfgrf g f Lawless Inorg. Chem. 1970 9 12 2796-2798. C.A.

Vol. 74, 12545 abstract only furnished. [22] Filed: Mar. 23,1973 Shreeve et al., J. Chem. Soc. D. 1970 (24) [211 App! No: 344,168 1679-1680, abstract only CA. 74: 52974.

Primary Examiner-Lorraine A. Weinberger 260/543 -63; 260/ Assistant Examiner-Richard D. Kelly A; 260/648 F 57 ABSTRACT [51] 29/34; (307d 27/02; Bis(dialkylamino)sulfur difluorides are new fluorinat- C070 145/00 ing agents [58] Field of Search 260/543 F, 293.85, 326.82,

4 Claims, N0 Drawings 1 BIS DIALKYLAMINO )SULFUR DIFLUORIDES BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to new bis(dialkylamino)- sulfur difluoride compounds which are useful as fluorinating agents.

2. Prior Art The preparation of dialkylamino sulfur trifluorides is described by G. C. Demitras, R. A. Kent and A. C. MacDiarmid, Chem. Ind. (London), 1964, 1712; and by G. C. Demitras and A. G. MacDiarmid, Inorg. Chem., 6, 1903 (1967). The F nmr spectrum was described.

S. P. Von I-Ialasz and O. Glemser, Chem. Ber., 103, 594 (1970) describe the preparation of (C I-I NSF by reaction of (C H NSi(Cl-l with SP This compound reacts with (CI-l SiN=C=NSi(CIl to give NCN=SFN(C l-l No other chemistry is reported.

S. P. Von Halasz and O. Glemser, Chem. Ber., 104, 1247 (1971) describe the preparation of RSF (R Me N, Et N and piperidino) by the reaction of R- Si(Cl-l with SP They report several reactions of RSF compounds, including:

W. C. Smith, Angew. Chem., 74, 742 (1962) review the use of SR, as a fluorinating agent.

W. A. Sheppard, J. Amer. Chem. Soc., 82, 4751 (1960); 84, 3058 (1962) describe the use of phenylsulfur trifluoride to fluorinate carbonyl compounds.

W. C. Smith, US. Pat. No. 2,859,245 and Schneider et a]. U.S. Pat. No. 2,983,626 disclose the process of preparing organic fluorine compounds by the reaction of SF., with carbonyl compounds.

DESCRIPTION OF THE INVENTION The invention is a new fluorinating agent of the formula The reaction is conducted by charging the dialkylaminosulfur trifluoride into the reaction vessel and then adding the aminosilane. Solvent is not necessary for the reaction but the use of an inert solvent is usually advantageous to moderate the reaction and to insure better mixing. Solvents suitable for the reaction include hydrocarbons such as pentane and benzene, halocarbons such as trichlorofluoromethane, methylene chloride, chloroform, and carbon tetrachloride, and ethers such as diethyl ether and tetrahydrofuran, or any other solvent inert to both reactants.

The reaction is conducted at a temperature of -C. to +50C. The preferred range is 030.

Pressure is not critical. Ambient and/or autogenous pressure is the most convenient and therefore preferred.

The bis(dialkylamino)sulfur difluorides can be separated from the reaction mixture and purified by the usual techniques such as crystallization, filtration, and distillation. The new difluorides are not stable for prolonged times at temperatures in excess of C. and purification techniques involving temperatures higher than 100 are not recommended.

SPECIFIC EMBODIMENTS OF THE INVENTION In the following illustrative examples all parts are by weight and all temperatures are in degrees Centigrade unless otherwise stated.

EXAMPLE 1 Bis(dimethylamino)sulfur Difluoride Anal. Calcd for C H, F N S: C, 30.3 N 17 7 5 l .65; F, 24.02; 26 Found: C, 30.

EXAMPLE 2 Bis( diethylamino)sulfur Difluoride 3,888,924 3 4 A 14 -1; mOle) Sample Of hyl m rim The bis(dialkylamino)sulfur difluorides are useful as thylsilane was added dropwise to a stirred solution of fluorinating agents. In particular, they are useful in rel6.1 g (0.1 mole) of diethylaminosulfur trifluoride in placing hydroxyl groups in sensitive organic com- 50 ml trichlorofluoromethane at 25. The reaction mixpounds with fluorine atoms, and can be used in the ture was stirred for 2 hr, until two liquid phases formed. preparation of fluorine-containing pharmaceuticals. The solvent and fluorotrimethylsilane were distilled off Th difl id are superior to other known fl i under reduced P at to g 1959 nating agents such as sulfur tetrafluoride and dialkg P Of bis(diethylamin0)sulfur difluoride as ylaminosulfur trifluoride in that they cause fewer side a light yellow liquid? mm a 3 pp J reactions, such as elimination of the hydroxyl group to and pp (q, J HZ, F 10 give an olefin, and less rearrangement. 11ml" s 5 pp For example, reaction of crotyl alcohol with sulfur tetrafluoride gives mainly butadiene (by elimination of the hydroxyl) and reaction with diethylaminosulfur tri- AnaLCalcd for CBHZOFZNZS. R1173 fluoride gives mainly 2-fluorobutene (by rearrange- Found: F. 17.92, 18.01 15 ment). However, reaction of crotyl alcohol with diethylaminodimethylaminosulfur difluoride gives the unrearranged l-fluorobutene as the principal product. Cyclohexanol is dehydrated by both sulfur tetrafluoride EXAMPLE 3 and diethylaminosulfur trifluoride to give cyclohexene (Diethylamino)(dimethylamino)sulfur Difluoride with only a trace of cyclohexyl fluoride being formed,

A 11.7-g (0.1 mole) sample of dimethylaminotrimebut when cyclohexanol is treated with bis(dimethylsilane was added dropwise to a solution of 16.1 g thylamino)sulfur difluoride an appreciable yield of cy- 0.1 mole) of diethylaminosulfur trifluoride in 50 ml of clohexyl fluoride is obtained. trichlorofluoromethane at 25. The reaction mixture The following examples illustrate the utility of bis(- was stirred for 1 hour. Two liquid phases formed. The dialkylamino)sulfur difluorides as fluorinating agents. solvent and fluorotrimethylsilane were removed by distillation at reduced pressure (25, 0.5 mm) to give 17.09 g (92 percent) of (diethylamino)(dimethylamino)sulfur difluoride as a light yellow liquid: H Fluorination of Crotyl Alcohol with 2 r6l'lc)cllilji) 11 3 4O (D1ethylam1no)(drmethylammo)sulfur Dlfluol'lde (CCl F) 8 +100 ppm (s).

EXAMPLE A Anal. Calcd for C H F N S: F, 20.40

ound: 20.62, 20:71 Cl-LDCIECHCH OH (C H5) NSF N(CH3)2 The following table includes several new bis(dialkylamino)sulfur difluorides that are included in this ino vention along with an equation that illustrates their preparation CH3CH=CHCH2F (c 11 11s11(cu TABLE Dialkylaminosulfur Dialkylamine Bis(dialkylamino)- Trifluoride trimethylsilane sulfur Difluoride H3 2 5 CH c 11 C2H5-NSF3 CH CH CH CH NSi(CH C H ,-NSF NCH CH CH CH:

A solution of l.44 g (0.02 mole) of crotyl alcohol (2- butene-l-ol) in 2 ml diethyleneglycol dimcthyl ether was slowly injected into a stirred solution of 3.7 g (0.02 mole) of (diethylamino)(dimethylamino)sulfur difluoride in ml diethyleneglycol dimethyl ether cooled to 78. The reaction mixture was warmed to and the volatile products were distilled out into a cold trap at reduced pressure to give 1.3 ml of a colorless liquid. Redistillation gave 1.06 g (72 percent) of a mixture of fluorobutenes containing 79 percent l-fluoro-2-butene and 21 percent 2-fluoro-3-butene (rearrangement product): bp 24-27; F nmr (CCl F) 6 171.6 ppm (m, 21 percent) and .2l0.0 ppm (m, 79 percent).

When the reaction was repeated using 2,2,4- tr-imethylpentane in place of diethyleneglycol dimethyl ether as the reaction solvent, a 65 percent yield of fluorobutenes was obtained consisting of 87 percent l-fluoro-2-butene and 13 percent 2-fluoro-3-butene.

EXAMPLE B F luorination of Benzyl Alcohol with Bix(dimethylamino)sulfur Difluoride A solution of l.08 g (0.0l mole) of benzyl alcohol in 2 ml methylene chloride was added slowly to a solution of 0.0066 mole of bis(dimethylamine)sulfur difluoride in 6 ml of methylene chloride cooled to 78. The reaction mixture was warmed to room temperature and mixed with water. The organic layer was separated, washed with water and then 5 percent Na'HCO and dried (MgSO Analysis by gas chromatography (g.c.) and F nmr showed that benzoyl fluoride had been formed in 91 percent yield.

EXAMPLE C Fluorination of Cyclohexanol with Bis(dimethylamino)sulfur Difluoride A solution of 1.0 g (0.01 mole) of Cyclohexanol in 2 ml methylene chloride was slowly added to a solution of 0.0066 mole of bis(dimethylamino)sulfur difluoride in 6 ml of methylene chloride cooled to 78. The reaction mixture was warmed to room temperature and water was added. The organic layer was separated, washed with water and dried (MgSO Analysis by go. and "F nmr showed that cyclohexene and fluorocyclohexane were formed in equal amounts; F nmr (CH CI 8 161.2 ppm (m).

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

l. A compound of the formula wherein R, R, R and R alike or different, are each a primary alkyl group of l to 6 carbons, or when R and R taken together, and R and R taken together, are 2)4 2)5 2. The compound of claim 1 in which R=R=R =R =-methyl; bis(dimethylamino)sulfur difluride.

3. The compound of claim 1 in which 

1. A COMPOUND OF THE FORMULA
 2. The compound of claim 1 in which R R1 R2 R3 methyl; bis(dimethylamino)sulfur difluoride.
 3. The compound of claim 1 in which R R1 R2 R3 ethyl; bis(diethylamino)sulfur difluoride.
 4. The compound of claim 1 in which R R1 ethyl and R2 R3 methyl; (diethylamino)(dimethylamino)sulfur difluoride. 